Pinpoint Test H: Insufficient Air Conditioning (A/C) Cooling - Auxiliary System

Climate Control System

Pinpoint Tests

Pinpoint Test H: Insufficient Air Conditioning (A/C) Cooling - Auxiliary System

Normal Operation

Under normal operation, the auxiliary A/C system provides adequate cooling based on the position of the function selector switch.

This pinpoint test is intended to diagnose the following:
- Thermostatic Expansion Valve (TXV)
- Vacuum hose
- Vacuum control motor
- Stuck or bound linkage or door



PINPOINT TEST H: INSUFFICIENT AIR CONDITIONING (A/C) COOLING - AUXILIARY SYSTEM

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H1 CHECK THE MODE DOOR OPERATION


- Ignition OFF.
- Remove the rear lower body side trim panel.
- Ignition ON.
- With the engine running, cycle the function selector switch between FLR and NORM A/C or MAX A/C.
- Check the mode door for operation between the heater core and evaporator core positions.
- Does the mode door operate correctly?

Yes
CHECK the TXV for correct operation. INSTALL a new valve if necessary. TEST the system for normal operation.

No
GO to H2.

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H2 CHECK FOR SOURCE VACUUM


- Ignition OFF.
- Disconnect: Auxiliary Vacuum Control Motor.
- Connect the vacuum pump to the vacuum supply hose.
- Ignition ON.
- With the engine running, cycle the function selector switch from FLR to NORM A/C or MAX A/C.
- Measure the supply hose vacuum.




- Is the vacuum between 61-71 kPa (18-21 in-Hg)?

Yes
GO to H3.

No
LOCATE the vacuum hose restriction or leak. REPAIR the vacuum hose as necessary. TEST the system for normal operation.

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H3 CHECK THE VACUUM CONTROL MOTOR


- Ignition OFF.
- Carry out a vacuum leak test on the auxiliary vacuum control motor.
- Connect the vacuum pump to the auxiliary vacuum control motor.
- Apply 61-71 kPa (18-21 in-Hg) of vacuum to the auxiliary vacuum control motor.
- Check for a vacuum drop.




- Does the vacuum drop?

Yes
INSTALL a new vacuum control motor. TEST the system for normal operation.

No
CHECK for a sticking mode door and REPAIR as necessary. TEST the system for normal operation.

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